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Can we trust the science of nutrition?
Professor Brian Cox and our expert panel dive into the complex world of diet, nutrition and food choices.
With new probiotic and high-protein products appearing on supermarket shelves every day and conflicting nutritional advice coming from every direction, it’s difficult to cut through the noise when it comes to what we eat.
Our panel uses expertise from their roles as nutritionists, geneticists, gastroenterologists and policymakers to answer audience questions about food advertising, wellness advice, and whether it’s really possible – or worthwhile – to avoid food ‘additives’.
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Brian Cox: Hello, I'm Brian Cox, and this is A Question Of Science, recorded here at the Francis Crick Institute. In each episode, we assemble a panel of world-leading experts to tackle your questions about some of the biggest scientific challenges we face today from AI to climate change, from cancer to consciousness. And today's discussion concerns the science of nutrition.
With over half of the UK population deemed to be overweight, and a quarter classified as obese, never has this question of what we eat been more important. We've all seen the headlines about ultra-processed foods and social media influencers who claim to know how to stay slim or be more healthy. But what does the science tell us? We've assembled a panel of experts to explore your questions about nutrition and they are.
Giles Yeo: Hello, my name is Giles Yeo. I'm a Professor at the University of Cambridge where I studied the genetics of body weight. So why people are small, medium and large in the current food environment that we actually live in.
Christina Vogel: Hello, I'm Christina Vogel, Professor of Food Policy and Director of the Centre for Food Policy at City St. George's University of London. And I lead a range of research projects ' that really aim to inform policy and practice to redesign our food systems so that everyone can achieve a healthy and sustainable diet.
Saliha Mahmood-Ahmed: Hello, I'm Dr. Saliha Mahmood-Ahmed I work in the NHS on the frontline as a gastroenterologist, I work in northwest London. I cook, I eat, and I won MasterChef in 2017. But my real passion is treating digestive health problems.
Nita Forouhi: I'm Nita Forouhi, I'm a Professor of Population Health and Nutrition, a public health doctor, and I head research in understanding how diet links to health and disease. And I do this in all different types of populations in the UK, in Europe, and in global populations such as in South Asia and so on. And I'm based at the University of Cambridge.
Brian: And this is our panel. So before we get into the detail, we thought we'd start with a relatively lighthearted question to introduce the panel. And we were thinking about what we should ask and we came up with what is your favourite food and in your professional opinion, what should you replace it with? So we'll start with that Giles.
Giles: First of all, do as I say it, not as I do. No, my favourite, my favourite dish actually is something called Hainanese chicken rice. My mum's dad is Hainanese. I know how to cook it. It's poached chicken. Okay? And you take the liquor and you make everything else with it. Chicken, the rice, the sauce and the chilli sauce.
Brian: That sounds healthy though.
Giles: No, I know. Exactly. So I'm not gonna replace it with anything, but it is divine.
Brian: Christina.
Christina: So I was gonna say avocado on toast smothered in olive oil with salt and pepper. But then I was thinking, well, what should I replace it with? Probably broad beans that are sourced locally in the UK and maybe not olive oil, but actually I think my real real answer is Tim Tams and what should I replace it with? Well, Brits would say Penguins, but they are not the same.
Brian: Saliha?
Saliha: I'm a massive crisp fiend, so crunchy, crispy, oh, I can't have one packet of crisps. I have to have multiple. And what would I replace them with? Well, nothing because crisps are just wonderful. However, I may look at the ingredients list and perhaps choose some kettle chips one day over something that's really, really full of the nasty stuff, but I will eat crisps.
Brian: Nita.
Nita: I love Indian food as well as a lot of other cuisines. And my go-to breakfast is aloo paratha. Which I dunno how many of you know that, but it's a double whammy of lots of potatoes and lots of white flour and it's fried in ghee. So that is my favourite. But knowing what I do, I try to replace it and I often succeed with chickpea flour instead and making what's called a chilla instead, which is great nutritionally.
Brian: Well thank you. So with that, let's go to the first audience question.
Judith Cousin: Hi, my name is Judith Cousin. I want to know why so much nutritional and dietary advice is conflicting. How do I trust what the panel members are saying in contrast to the podcaster who's telling me everything I've been told is wrong and I should listen to them instead?
Brian: Saliha?
Saliha: It's a really interesting one. Anyone who sees nutrition in black and white is probably giving you an incorrect answer because most nutrition I personally feel exists in a shade of grey, which is what makes it so sexy to be honest as a topic of study. So I think what I'm very personally wary of social media or other messages where a particular viewpoint is being pushed very aggressively. And my advice to people is to question that because like many other parts of science, there isn't really a black and white to this.
Brian: And I suppose implicit in the question is where should you go?
Saliha: We have to acknowledge that social media is where people are looking for nutrition-based advice and therefore credible nutrition professionals need to have a bigger social media presence and need to be heard. And they need to get outta the discomfort that social media puts them in and really put their messages out there.
Brian: Christina?
Christina: Misinformation around nutrition is very prevalent and what I guess I'm interested in is the root cause of that. And I think it's because food is a commodity. People are trying to make money on food. And that actually inherently means that disinformation/misinformation makes money because it confuses people. Our food industry has a real role to play and they do an excellent job at feeding us, but we also all genuinely know what we should be having.
In the 1970s, actually what really was linked to cardiovascular incidents and poor health then was eating too much meat. And what happened was the lobbying and the influence of the meat industry in America actually diluted that and made it about nutrients, which then made it more confusing for consumers. And that's when nutrients really started to enter into dietary guidelines. We eat foods, we're interested, we eat foods in combination and meals and actually that's how we understand foods. And I think Michael Pollan has a really great sort of slogan to follow: eat food, not too much, mainly plants.
Brian: Nita.
Nita: Yeah, so I think nutrition science is really complex and that's why there's so much conflict out there. I would say it's hard to assess to measure diet. There aren't really very many objective ways of doing it. We rely on people, you know what they tell us. But I think we also need to remember that nutrition science, like all other science, good nutrition science does evolve. So there are changes and you know, evolution of science to get better answers with better methods.
And I think a third thing that's really important here is nutrition science gets played out in public view way more than absolutely any other science that I'm aware of. And everyone feels they know food because everyone eats, right? And their deeply held beliefs and perceptions about food, even emotive, you know, feelings about food. So we need good podcasts, hopefully like this one, where we talk solid science.
Brian: Giles, this is relevant to many areas of science, isn't it? How to communicate not only uncertainty but also the progression of knowledge. So the fact that advice changes as we acquire more knowledge, I suppose as Nita said it, in food you kind of, maybe the assumption is well, our grandparents knew all there is to know about healthy eating.
Giles: The problem is, I think there is a failure in the communication, not of data. In which a lot of us communicate, but in the scientific method that we are literally paid to argue with each other as scientists and then change our mind. Should our mind need to be changed. And so that needs to be put out there. And this includes nutritional science. It's a very public science. I can see what's in your plate at a restaurant, I can see what's in your shopping trolley at the supermarkets and I can equate it to your body and think, 'hm', right? And so we all do this. I don't do it, but we all do this, we all do this. But ultimately I think we have to crack that.
Brian: Why is it such a complex area to study? Is it to do with the fact that you're talking about your whole populations and large data sets and so on?
Nita: So I think it's the sheer volume of what diet is. So if you ask all of us and indeed the audience members, we'll all have different definitions. And there are hundreds of thousands of variables within it. So to break it down, essentially it is overall dietary patterns within which you eat foods and then foods get translated into nutrients. Like what we all know about fats, carbohydrates, protein, and thousands of micronutrients, vitamins, minerals.
So that's the complexity. And what happens is people are just picking off, oh, I'll study vitamin C or somebody else will say, but I want to study the Mediterranean diet or ultra processed foods and then we play it off against each other, that's the complexity.
Giles: And then there's a fundamental scientific issue of which it's difficult in terms of within nutritional study to do the two things you need to do to really get a gold standard. Like if you're testing a drug, okay? It's easy to blind because you have a true placebo, you can blind the person giving the drug, you can blind the person taking the drug, you break it, there's no bias at all. You can't blind someone on a keto diet and you can't placebo intermittent fasting. So it has to be observational. So I think fundamentally with the specific field of science, it's always gonna be difficult because you can't double blind control.
Brian: Well we have a question actually from the audience which feeds into this discussion about the complexity.
Barbara Sciecko: Hi, my name's Barbara Sciecko. and I want to know if it's possible to scientifically measure the impact of food additives and emulsifiers on humans given that our DNA, lifestyle and environments are all different as well as the cocktail effect of consumption of different food stuffs.
Giles: I think you can test each individual thing, a specific emulsifier, not emulsifiers in general because there's a whole class of things in itself. You can say that, okay, this is some weird emulsifier, we want to know if it's toxic. And so we're not gonna feed it to a human being. So you have to use other studies in order to then determine, first of all, is it toxic? No, alright, is eating too much of it going to increase risk for the disease? Yes or no? And that's just one emulsifier. Then you break it down, then you go, okay, then E, this E number, E number sounds scary, but not all E numbers are bad. And you sort of move from one to the other. The issue is asking the specific variable rather than saying fats, emulsifiers and things like that.
Brian: I suppose maybe there's an assumption there, maybe that's too strong that additives are bad. So additives, emulsifiers, so fresh locally grown produce is by default the best thing to do. Is it too simplistic to just say, well avoid additives?
Saliha: I think it's a really interesting question. I spend a lot of time with patients sort of demystifying the fact that not all foods fall into the category of good and bad, okay? And yes, we are understanding more about emulsifiers and in my fields the impact that they might have on our gut microbiome and gut health.
But fundamentally there will be foods which contain emulsifiers that still have other things which are beneficial for you in them. So I'm always very concerned when we have this approach whereby in nutrition and in food we vilify certain food items. And say, well, all of this category of food is bad for you. But I do believe, as you've said, that actually there needs to be more science for us to get to a position where we can give population level guidance to people about how much emulsifier is an okay amount to have.
Brian: And how much of a role does legislation play? 'Cause clearly there are particular substances and additives that will be outlawed at some point. So what's the balance between legislation and then information and choice?
Giles: Well, I think there's an issue of what is poisonous? And that I think that is a black and white kind... that we can go with. I think it's this concept of risk, right? I mean, come on, smoking is still legal and alcohol is legal and both are toxic, okay? I love alcohol, this is not- but both are toxic. So I think that public health is an interesting space in a complex field because there's always this tension in public health behind how much personal liberty are you willing to lose?
Christina: Yes.
Giles: For the greater good of society? Now this tension is going to have to be accepted by society, it's gonna be culturally specific, but you gotta get society on board, whatever the science says so that you don't get a riot. We are nowhere near there with food because whenever we discuss food, there is hysteria, we talk about one thing is bad, one thing is good, et cetera, et cetera.
Christina: This whole conflict between personal liberties and personal choice, yes. But at the moment we don't really have personal choice. You know, the cost of fruit and veg is double per calorie what high-fat, -salt, -sugar foods are. Our high streets are absolutely dominated by fast food and takeaway and convenience outlets. So people that are at risk of obesity and poorer diet, it's largely being shaped by their food environments.
And marketing is a whole nother level. Do you know, we are bombarded by adverts not for fruit and veg, not for beans and pulses, but for a whole lot of foods that are high in fat, salt and sugar. And that is where it is important that government take a role in encouraging and nudging and supporting industry to reshape our food environment so that they match our Eatwell Guide. The estimated cost is about 90 billion per year of obesity and poor diet on productivity as well as the NHS. So productivity losses, so people being sick and not being able to work.
Brian: Well we do have a question actually the next question on the interaction between medical advice and nutritional advice.
John Wojciow: Hi, my Name's John Wojciow, Hippocrates said, "Let food be thy medicine." Why isn't food and the science of nutrition utilised a lot more in medical advice and treatment.
Brian: Saliha?
Saliha: Yeah, he was a clever man, Hippocrates, wasn't he? And he knew this so many years BC didn't he? Why do I think it doesn't happen? First of all, for many, many years, nutrition wasn't taught in medical school very well. So there is a huge lack of food-based knowledge in a whole, not even one multiple generations of doctors actually. Now, even when you do become a doctor, taking a nutrition history from a patient is quite a nuanced task to do. And it takes a bit of time.
And actually when you're in the thick of it and you've seen a patient in the middle of A&E, sometimes the priority at that moment in time is not taking the nutrition history. But I am personally very deeply passionate that in clinic settings where we see patients more electively, we are trained to do nutrition-based histories to take a non-judgmental approach. And actually that involves providing practical advice.
And I go as far as saying, okay, well what are the foods that you like and how can we adjust or manipulate your diet? So we include some of the things that you still like because there's no point I feel giving someone a picture of the Eatwell Guide, and saying to them, well you've got fatty liver disease, you need to lose weight and come back to me with better liver function tests - eat like this. When, you know, they may not be able to afford any of the food on the Eatwell Guide. They've maybe never eaten the types of food that you're presenting to them. So yet I think there's a lot of work yet to be done.
Brian: Nita?
Nita: Yeah, and to add to that, at the moment we have a disease service, not a prevention or a health service largely. So we only get to see the dietitian pretty much when we've already become overweight or obese or we've had diabetes or a heart attack or a stroke or cancer and so on. So I think that model needs to shift as well. And there's evidence that when people go on better, healthier food, their weight comes down, their glucose control improves and so on.
Brian: There's a question I just wanted to ask from the audience from Dan Twining who said, why can't scientists and food manufacturers make healthy food that tastes as good as unhealthy food? So, which is actually quite a deep question, isn't it? Why are we drawn?
Giles: No, no, it is a deep question. I once did a talk for a major confectionary manufacturer about obesity and the guy asked about this particular chocolate bar, well what should we do? And I said, you need to make this chocolate bar taste like a chocolate bar, look like a chocolate bar, cost as much as a chocolate bar, but not be a chocolate bar. But it's true, it is true. And I think the problem is the right incentives and yes, I realise that the best thing is to eat whole foods, but if we are pragmatic about the situation that we need to deal with the foods that are there, I do believe the science is there, the expertise is there to reconstruct some of the foods there to make them healthier.
Will they ever be healthy? We debate that, but healthier. We just need to put the right incentives in place. And I think the right incentives without sounding like a Reaganite, is going to be market. And I think what you've gotta do is to either through government intervention or something, legislate the changing of the food system to something healthier so that the companies will actually do it.
Brian: Why are we drawn to things like crisps for example? Let's take it, so this salty, high-fat thing, what is it? It's our evolutionary history I suppose.
Giles: There is an evolutionary history. I mean the... Well look we're all mammals, last I checked. And so we drink milk. And so what is the role of a baby mammal or baby mammals when they pop out? It's to latch onto the highest energy source of food available, the boob, okay? And to grow quickly to avoid becoming tiger food. Now this is ultimately still ingrained within us, which means eating high energy foods.
Now when you think about milk, it is probably one of the very, very, very few naturally occurring foods that is high in fat and carbs together. Now I'm not talking about frying a potato that's adding carbs to fat, but actually naturally together. And so if we now look at a lot of the ultra processed foods, they are this magical mix, right? Between the fat and carbs that I guess in some ways call back to our instinct of liking this high energy foods.
Christina: And the term is hyperpalatability.
Nita: Yes.
Brian: Hyperpalatability?
Chrstina: So yeah, I mean there's some good evidence that manufacturers have worked for this exact formula and proportions of carbohydrates to fats to actually design those into foods. And then they heavily marketed and then they're priced quite cheaply and you know, you get a match made for commercial heaven, which makes it more challenging then for us to sort of resist.
Brian: Well, thank you. Let's go to the next question.
Christine Hewitt: Hi, I'm Christine Hewitt, and my question is, can we nurture our gut flora via our diet in the way a number of food and drink products claim? And do we need to?
Brian: That's a very good question. I should say that we have a model of a gut that we should... This is really bad audio, but I think its fascinating nonetheless.
Giles: So this prop, which I will show and then I will let the gastroenterologist in the panel speak to it.
Brian: Yeah, just to see what we're talking about here.
Giles: So this is a life-size knitted, thank you to the Burwell WI, Women's Institute, who knitted this for me. And this is life size. So I'm gonna pass it along along if we can. This is the tongue, oesophagus, this cacophony of pillows over here is the accessory organs. Okay? So this is the small intestine, okay? That is not so small. And then, and it keeps going. This is the appendix.
Brian: How long is it?
Giles: 21 to 22 feet, depending on whether you are 6'5" or 4'2".
Brian: And it can be used as a scarf.
Giles: I know exactly. Lady Gaga's food scarf.
Saliha: Well I am glad you brought this out actually because this is not an inert thing, right? So this gut will contain roughly two kilograms, if not more of material, which is all your juicy sloshing around microbes, those microbes-
Brian: Two kilograms.
Saliha: Yeah, huge, that's a gargantuan mass of microbes in there. And they are unique to you, as unique as your own fingerprint is. Nobody in the world has the same microbiome as anybody else, okay? Which is amazing. The microbes that live inside you, they are in a state of flux. So you can change the way your gut microbes are and in turn they can have a beneficial or indeed a poor impact on your health long term. How you can really optimise your gut health is to have, and it's a very simple message, as much whole food, plant-based diet as you possibly can. Okay, I'm not a vegetarian, I'm not a vegan. However, a diet where you have whole grains, okay, nuts and seeds, fruit and vegetables, pulses, legumes, spices, the good stuff, okay?
And the more of that you can have the more dietary fibre you have, fibre, the forgotten nutrient, not even considered a nutrient by some, but it's so important to this bad boy here. And by improving the amount of fibre that you have in your diet, I think that is the first and most important fundamental change you can make to your gut health. Then we come onto the realm of, well should I have supplements or probiotics in the form of manufactured goods? Well I have to say, I'm always very careful when I'm telling people to part with any of their own money, particularly when there are good homemade solutions, okay?
So something like a lovely natural yogurt has loads of good microbes in it. Rekindle that relationship with your sauerkraut jar, you know, it's worth it. We are losing this connection that we have to fermentation this connection to microbes that actually is very fundamental to us as human beings. So I'm very much for home-based fermentation and seeing if you can make food-based solutions rather than going out. So in summary, the food that you eat is basically able to really improve the health of your microbiome and in turn that has huge impacts on your health. And dietary fibre is probably the critical part of all of that.
Brian: It's the same advice that you've given in the answer to every question, isn't it, basically? Which is whole foods and vegetables and fibre. So it's quite a relatively... Although we've said it's a complicated subject, there is a simple message there. In that sense
Saliha: It can be distilled.
Nita: You know, why is it that the whole foods are better? So there are trials, clinical trials of when isolated nutrients from foods have been taken like betacarotene or vitamin C, if you take those pills, there isn't really a benefit shown and there's a multi-billion dollar industry in all these supplements and so on. But when you eat the fruit and the vegetables from which these are sourced, there are health benefits.
And the reason is, again, going back to that complexity, if you take a given fruit like an apple or an orange or even a banana, whatever, it's got thousands of things going on inside it in the food matrix. So if you just take the isolated nutrient, you are losing all those other things, including fibre and vitamins and minerals and so on. And the same thing I think applies to probiotics. If you take them as a supplement, you're getting only that thing. Whereas if you have it from the natural foods like yoghurt or fermented foods and the fibre part of it, then you're getting all the other goodies that are part of the food matrix as well.
Giles: Gonna pass back my gut. Just in case I know we're gonna get looked at by the producers. I already feel the stare. I'm sorry.
Brian: Well we have a question, another question from the audience now, that's something we haven't discussed too much yet actually, which is about protein.
Jane Habib: Hello, my name is Jane Habib, and I'm curious what your thoughts are on high protein foods that are available now in lots of supermarkets.
Brian: Nita?
Nita: Okay, so there's a real protein mania out there now, and this is kind of history repeating itself, where at one point the food industry followed the scientific publications and research when they made low fat products and everything was low fat, low fat, low fat. But what happened instead was sugar was added and we, you know, still have increasing rates of obesity because we focus on one nutrient.
And the same is happening now with protein. So at a population level, on average we are getting far more protein than the body actually needs. So the need is around just under a gram per kilogram of your body weight. So for a 70 kilo man that's about 56 grams per day, and for whatever a typical woman is, at 60 kilos, that would be around 48 grams. And our average intake is way more than that. So it's the worried well who are being trapped into going for all these protein products.
There are special groups in the population who do need more protein. So as we age we need more protein because we get muscle loss and post-menopausal women are more prone to getting what's called sarcopenia and so on. So yes, protein is important, but it's being pushed way too much now. It's boring perhaps, but it comes back to the whole foods. For the protein, go to the food sources because again, these protein powders and shakes and so on ultimately have all sorts of things added to them.
Saliha: The protein powders actually constipate a lot of people, really do. And they also really give lots of digestive issues to lots of my patients. And actually the solution to this is, to not think so much about protein. Rather let's focus on the forgotten nutrient, which we actually aren't getting enough of, which is fibre.
Nita: Absolutely.
Saliha: And lots of people don't know that they need 30 grams at least of fibre a day. You know, over 80% of us I think are not actually getting that.
Christina: 8%.
Saliha: Only 8%. There we go. So you know, it's ludicrous really that we're focusing so much on protein.
Brian: So only 8% of those are getting enough fibre.
Nita: Yeah, that's from our national diet and nutrition survey, the latest report.
Brian: So what would be your recommendation to remedy that? People that are listening, what should they eat more of every day?
Nita: Whole foods. And for the protein needs, people automatically think protein means egg. Or dairy or meat, animal sourced foods. But actually you could get a pretty complete set of amino acids from a plant-based diet.
Saliha: If there's one thing you are going to count, count your fibre, you will learn how to improve the amount of fibre in your diet. And it can be as simple as swapping from white to brown bread. It can be as simple as adding a tablespoon of flax or chia seeds to your porridge in the morning.
Brian: And in terms of just on additives, because you can take fibre supplements, but it is the advice the same again, that you should really. The best way to do it is eat it as part of a food and not just something you sprinkle on these kinda supplements.
Saliha: Like many, I believe, yes we should have it as food. I also think that if you are on this mission to increment your fibre, please do it slowly, okay? For the benefit of yourself and others you live with. It's really, really important to do it slow. So don't just go from here and go right I'm gonna do it and then go, "oh, I hate her" the next day.
Brian: Well we have a question now about ultra-processed food.
Lesley Thomson: Hi, I'm Lesley Thomson, and I just wanted to know if you feel that all ultra-processed foods are harmful? And what are some of the less visible ultra processed foods that we may think are healthy options?
Giles: I question the definition of the ultra-processed foods. I think ultimately that is the issue. It's too broad a church. In this country, about 50% of our calories come from ultra-processed foods. So anything that's prepackaged, anything that has been and put into sort of some kind of container is pretty much ultra-processed I think there are uncontroversial foods that we would look at and most of us would go, ooh, maybe we should have less of rather than good or bad. Maybe we should have less of these.
But there are a lot of foods that are industrially processed. This is what ultra-processing is. It's not fermentation, it's not cooking, it's not brewing, okay? This is processing of food that has kept us alive. Ultra-processed foods are industrial processes that we cannot replicate within a domestic situation. And that can be off-putting to some people and there's some foods that are less good for you, but they're actually a whole lot of foods that get caught in this vacuum cleaner of ultra processed foods definition, which are industrially processed but not actually bad for you.
And so I think we need to go back to more empirical descriptions of our food. I like salt, sugar, fat, fibre, protein, you know, things that we can measure as a gram in front of it. There's something that we can talk about. So in answer to your question, no using the current definition of ultraprocessed foods, not all ultra-processed foods are bad for you and some foods which you don't think are ultra-processed at all are actually ultra-processed. There's a halo of health around certain types of foods. Oat milk for example, right? If you can convert milk from an oat right then by definition it's ultra-processed. Just people don't think about this. Anyway.
Brian: Christina?
Christina: I just wanted to chip in really that to say that the jury is still out. There's not hard scientific evidence that ultra processed foods are bad, that they should be excluded exclusively from our diet. I think some of the definitions get confused sometimes and as Giles said, we don't really have a good scientific definition yet. There's lots of work that's being done around that. There's been some really good research that looked at the overlap using national diet nutrition survey between ultra processed foods and foods that are high in fat, salt and sugar. And the overlap is about 59%.
So do you know it's reasonable but it's not exclusive. And I think one of the things that would be useful to start to think about, to directly answer your question is actually for consumers to understand which products meet that benchmark of being high in fat, salt, and sugar. And that a front of pack label to say this food is high in fat, salt, and sugar, so you know very clearly which ones the Government is saying "You should be having fewer of these foods." It would also help with legislation. So it would help with enforcement of our current rules that are supposed to ban high fat, salt, sugar foods in prominent places in our retail food outlets. It would also help with the advertising ban that's coming in.
Brian: So you said salt, sugar, fat. There is a question from Ellie Ton here, who wants to know what the evidence is that reducing salts in processed foods improves population health? So do we have good evidence?
Nita: Yes we do, so in the early 2000s, up till about mid-2015, 2016 or so. There was a government salt reduction programme in this country and that had the food industry reformulating and producing foods that were still palatable, tasty, et cetera. But they had reduced the amount of salt in them.
Some very nice work was done by colleagues here at Queen Mary University, London and other colleagues, which showed that it had very impactful influence on reducing hypertension and cardiovascular disease, strokes and heart disease and so on. So it is real, it works because the evidence is pretty solid, but at some point that government policy changed and the responsibility then went to the food industry itself and those gains that had been made have been plateauing. I'm sure Christina, you can add more to that.
Christina: Yeah, I agree. I think that's again where government regulation is important because it levels the playing field. So where everybody does that together, an incremental reduction. You know, there was a really good scheme that tried to really reduce by 20% say in cereals and in some yoghurts and other foods that are everyday foods that really don't need the level of sugar that they have. And they did reduce them, but it wasn't universal.
And so some of those sugar contents have now come up. So those voluntary schemes are not as successful as an incremental reduction that is mandated that says if you are identifying as this kind of yoghurt or this kind of cereal, breakfast cereal, therefore we should be reducing your sugar content by so much over 10 years or something. And that would have a huge impact on the population's health.
Saliha: As a chef I think, you know, you can reduce salt down by increasing flavour from other spices. And we have a whole world of spices out there where we can experiment and actually create products which are wonderful, new and diverse, but still have that lesser salt. Here's me saying I love crisps, but there are some salty snacks which have more concentration of salt in them than seawater. I mean that is insanity. And those same products have what we call a health halo around them. So they are marketed as being good for us, you know? In other ways, higher fibre or higher protein or whatever it is. So we've gotta really like take a bit of a nuanced approach here and see where the role of chefs and creativity lies in salt reduction.
Brian: Let's go to the next question, which is about obesity.
Sophie: Hi, I'm Sophie and my question is about weight loss drugs. I've used Mounjaro with great success, after years of following nutrition advice that never really worked for me. Does the effectiveness of drugs like this suggest that nutrition science has underestimated the biological drivers of appetite and weight? And if so, can we still fully trust the science that told us diet alone was the answer. And how should nutrition science respond to the fact that a drug is now doing what decades of dietary guidelines could not?
Brian: Giles?
Giles: So, ooh. Listen, okay. You are asking two separate questions. The nutrition science, and I'm not a nutrition scientist per se, is there to improve your diets, what's healthy, what's good, what's bad for you. But you can still eat too much good stuff and end up with, for example, obesity, overweight, and things like that. Then there's gonna be the drivers, which is what I study. On what makes you more drawn towards food, healthy or unhealthy and therefore end up eating more and still end up having obesity because you can have obesity even with a wonderful diet, but just way too much of it.
And so I think if you take that question into two parts, then we still need the nutrition advice. We still need the policies to improve our food environment because that will prevent obesity, okay? And that will improve our health. The drugs that are that are there, they're powerful. They are a drug, they're not a cosmetic tool, but the drugs that are there are very useful to treat obesity. And I need to declare interest here that I do advise a lot of the major pharma companies about how these drugs work. Just thought I'd tell people that.
Christina: I just wanted to say I don't think it's an either/or. As Giles said, we need both. So yes, there will be cases where, you know, obesity drugs are needed and necessary as a short term sort of kickstart to then following a healthier dietary pattern and being able to maintain a healthy body weight. I think some of the major risks are for me around nutritional density and quality of diet. So if people are taking obesity drugs and following the same unhealthy diet, actually there's real risks of nutritional deficiencies and we're already seeing them.
Do you know there's about 11,000 hospitalisations each year due to nutritional deficiencies and most of them are scurvy and rickets. I mean they are things that are decades, you know, in the past- centuries in the past and we're seeing them again. And largely again, it comes back to whole grain foods and fruits and vegetables and it's just not having enough of them. We definitely need the food environment policies to reshape our food environments so that we are getting good nutritional quality as well as having obesity drugs where they're needed.
Brian: So it's essentially the point that if you're eating less, you have to pay more attention to the things you really need to be eating?
Saliha: Correct.
Nita: Yes, and I would say it's not that the nutritional advice has failed, our food environment and what's available to us as cheap energy dense calories is to blame. With these anti-obesity drugs, if you stop taking them, the weight goes right up a 100% percent as well. So either you take these for life or you take them as a trigger to learn about how to eat better and physical activity of course we shouldn't forget.
Saliha: I feel really importantly that we have to understand obesity as a phenomenon. For me, obesity is a disease, okay? There is no black and white about this. Obesity is a disease. The characterisation of the disease is feeling hungry all the time and never feeling full. Those are the symptoms of the disease. And chronic illnesses and diseases require treatments and we now have treatments, albeit flawed to a certain degree, but we do have helpful treatments which help in this disease, which we call obesity.
Now I think of obesity almost like putting a radio on, okay? So all of us have that natural ability to gain weight, but many of us are able to just have that in the background and our weight is stable, but our environment is like the volume on that radio and it can really dial up or dial down whether you then become obese or not. And that's where we've gotta tackle this front on and say, actually the nutrition advice goes hand in hand with drugs like Mounjaro et cetera. But fundamentally, unless you start visualising obesity as a disease process, you will not give it the due credence that it deserves.
Brian: Well we have time for one last question, which is really I think bringing everything we've discussed together.
Becky Tucker: Hi, I'm Becky Tucker, and I would like to know if we are close to being able to provide reliable personalised diet recommendations? Or does the weight of current evidence still suggest that whole food, plant-based patterns are broadly beneficial across populations?
Brian: I'm tempted to say we can all agree on the second, but it's a very good question because we discussed it before briefly in medicine there's very tailored advice. And drug use is becoming more and more tailored to the individual, is it the case in nutrition?
Giles: It's a very difficult question because the very, very first points we made about how do we measure, how do we measure the nutrition. Within the genetics of metabolic disease, what is the strongest link between genes and metabolic disease is actually the type of metabolic disease you end up getting when you actually end up carrying too much fat. So that we have a very, very good idea on.
Now the moment we get into a situation of trying to ask, well now with your genes versus you should be on a Mediterranean diet, or keto or vegan, then it becomes far more murky no matter what people say, the science is not there yet. I think ultimately if we get our messages from here, meaning stick to a whole food diet, you know, and eat minimally processed foods, I think on average that will benefit pretty much everybody in this room.
Are they gonna be people who benefit from it more than me or me less than someone else? Undoubtedly. Okay, because why would that not be the case? But I think we are quite a bit away yet of measuring diets properly so that we can link it to the genetics. But there are gonna be genetic differences between how we respond to even a whole food, minimally processed diet.
Brian: I get the sense you're suggesting they would be marginal relative to the broad sweep of the advice. So you're talking about smaller changes.
Giles: They're gonna be smaller changes because I will struggle to identify a large enough population of people to be relevant who are going to be harmed by a whole food, minimal processed diet. You never know. There are obviously gonna be some people, but the vast majority of humankind, this is going to be good. And yes, there are gonna be marginal differences between me and Nita and Saliha and you know, and that's just gonna be the case.
Saliha: I believe that there will be a time, and I hope that it's in my career, where we are more succinctly able to personalise nutrition advice for patients. But I don't believe that time has come now. And I believe that anybody who tells you that that time has come now is probably not telling the complete truth.
But for me in the meantime, personalisation of nutrition happens in your kitchen. And cooking is fundamentally important and is actually the very tenet of the conversation that we've had today. We keep talking about nutrition, actually what we're talking about I feel is cooking, okay? Getting into the kitchen, there's this lovely Latin saying, which is "Coquo, ergo sum." I'm sure I've pronounced it wrong, but it means "I cook, therefore I am." And that is true, okay? There is no other creature on planet earth that can cook, okay? From an anthropological standpoint, it is a fundamental activity that defines us as human beings. It's likely what made our gut shorter and what made our brain bigger and made us the sophisticated beings that we are today.
So in schools is where personalisation of nutrition really starts. We teach toileting, we teach literacy, we teach numeracy, we teach sex education, we teach religious studies. We teach modern foreign languages, which we never use. Yet we don't teach nutrition and cooking. So how do we expect them to have the skills to be able to look at a pack and interpret the counts on it? How do we expect them to be able to avoid ultra processing of food? We can't expect those things if we've never taught it. So personalisation happens in your kitchens.
Brian: I was going to go around the panel actually for the... 'Cause we've run out of time, to say what's the 30 second piece of advice, but you've just given your 30 second piece of advice very eloquently. Well, maybe I'll give it. So Nita, what would you say in summary, if someone wants the quick answer to what we agreed was a very complicated problem.
Nita: Go for the whole foods, wherever you can. And yes, life happens, life is busy. We have kids, we have work, we have caring responsibilities, and you know, various takeaway facilities are right there. But cooking at home and whole foods really make a difference.
Brian: Christina?
Christina: I'm gonna slot two in quickly. One is try a bean and pulse that you haven't done before and incorporate it into a dish that you love. The other one is about take a note of your food environments and if you're starting to feel a bit frustrated about your food environment, write to your MP. The government are currently developing a food strategy, a national food strategy, and we want health and sustainability to be part of that.
Brian: Giles?
Giles: Everything in moderation, including moderation. I think I paraphrased that, but I think so. So I think that's probably the case where we need be moderate, including the odd time when we are immoderate.
Saliha: Hooray, crisps!
Brian: I'll sign to that one. Well, thank you to our excellent panel, Giles Yeo, Nita Forouhi, Christina Vogel, and Saliha Mahmood-Ahmed.
